The present invention relates to a conveyance apparatus, conveyance system and conveyance method, which are suitable to convey a load which must be conveyed without being touched, such as a molding material.
Concerning conveyance technology for conveying a molding material such as an optical element material which is used for forming a lens, well known is one which touches and absorbs the optical element material, and conveys it to molding dies, using an absorbing pad made of Teflon or a heat-resistant rubber mounted on a conveying arm. The optical element material is heat-softened by a means such as infrared lamps arranged around the molding dies. After molding, the optical element material is absorbed by the absorbing pad and collected.
In this case, if the optical element material is heat-softened during conveyance, it is possible to shorten the molding time, however the optical element material must be conveyed under a fused condition, and accordingly, there is a problem that the above-mentioned touching and absorbing method is not suitable for conveyance of the fused optical element material. Further, concerning a method to convey the fused optical element material mounted on a conveyance member having a built-in heater, there are problems that fusion bonding between the conveyance member and the optical element material must be prevented, and still further, there is the problem of uneven heating. Concerning these problems, TOKKAIHEI 8-133758 discloses a technology by which the optical element material can be conveyed without coming into contact with the conveyance means.
According to the technology disclosed in the above mentioned TOKKAIHEI, though it is possible to hold the optical element material in a floating condition by a hot air blast which jets out from the bottom of a funnel-formed holding device, there is the problem how to throw the material into the molding dies. FIGS. 12 and 13 show the structure of the above-mentioned disclosure. The disclosed holding device holds optical element material 1 by holding sections 317a, 317b, 319a, and 319b which are hinged on pivots 318a and 318b so that holding sections 317a and 317b, and 319a and 319b are separated, whereby, optical element material 1, supported in a floating condition, drops down into the molding dies. This however requires a structure in which holding sections 317a, 317b, 319a, and 319b can pivot and are adjustable, which results in a large sized device, further the molding apparatus requires space wherein each holding section can move, resulting in a large molding apparatus. Yet further, if the rotating speeds are slightly different of the two pivoting holding sections, the optical element material is subjected to a momentary one-sided force, so that it cannot drop down vertically, by which the essential accuracy at the predetermined position is inadequate.